You may have the answer already. I see this is an older post. I work with video files in Logic daily and initially had the same issue. Very frustrating. I found that part of it came down to the video format/resolution I was using. Logic runs MUCH smoother with .mov files. If they are too high res, they can also cause significant delay. I try to strike a balance so I can still have pretty tasty resolution but great performance too. If you don't already have this free utility, go to http://www.squared5.com and download MPEG StreamClip. This program lets you change the format of your video file so it plays nicely in Logic. Good luck.